THURSDAY, May 30 (HealthDay News) -- People with a severe case of the flu don't benefit from taking double doses of the antiviral drug Tamiflu, according to a new study conducted in Southeast Asia.

Tamiflu (oseltamivir) stocks could be conserved during pandemics if doctors prescribe only standard doses of this medication, World Health Organization experts suggested.

The study involved 326 patients diagnosed with severe flu at 13 hospitals in Indonesia, Singapore, Thailand and Vietnam between April 2007 and February 2010. Most of the patients were children younger than 15, but some adults also were included.

Health-care workers treated the patients with either a standard dose of Tamiflu (75 milligrams twice daily or the children's equivalent), or a double dose of the medication (150 milligrams twice daily or children's equivalent) over the course of five days.

Patients' virus levels were measured through nose and throat swabs. Researchers then tracked how many patients died, were admitted to the intensive care unit or required the help of a ventilator to breath.

After five days of treatment, there were no differences between the patients on a standard dose of Tamiflu and those given the double dose. Moreover, no differences were seen in death rates or other adverse events, the study found.

The findings were published online May 30 in the journal BMJ.

The study authors concluded that there's no added benefit from a higher dose of Tamiflu to treat severe flu, according to a journal news release.

In an accompanying editorial, Ian Barr and Aeron Hurt from the WHO Collaborating Centre for Reference and Research on Influenza, wrote that a double dose of Tamiflu "is unlikely to significantly improve the clinical outcomes of severe cases of seasonal influenza."

They added that the study's findings "could help to preserve oseltamivir (Tamiflu) stocks during a future pandemic if clinicians were to prescribe only regular rather than double doses." They noted, however, that flu treatment options must be expanded and further research is needed on more effective combinations of drugs.